Answer
No — direct write access to the application server's own filesystem isn't available in IFS Cloud, unlike on-prem environments where a shared path like filerep1 was directly accessible. This is a confirmed platform limitation, not a configuration or credentials mistake. The supported alternative is to use FTP instead: configure an FTP Sender/Receiver pointed at an actual FTP-accessible location, and change your Routing Address to use that FTP sender rather than trying to write directly to a server directory — this is the way to test and run outbound file-based integrations in Cloud.